Endometriosis refers to the presence of endometrial-like tissue growing outside the uterine cavity, such as on the fallopian tubes, ovaries, or surrounding areas of the uterus. It is one of the causes of menstrual pain and infertility. According to the classification by the American Society for Reproductive Medicine, endometriosis is divided into four stages. While stage 1, which represents minimal endometriosis, may not significantly affect fertility, stages 2 to 4, which include mild, moderate, and severe cases, can reduce the chances of natural conception. Endometriosis is currently one of the leading causes of infertility, affecting nearly one-sixth of infertility patients.

 

These ectopic endometrial tissues are also influenced by ovarian hormones and undergo cyclic changes similar to the normal endometrium. They proliferate, shed, and produce menstrual-like bleeding. However, since the menstrual blood cannot be expelled from the body, it stimulates other tissues, leading to inflammation and adhesion formation. Over time, the accumulated menstrual blood turns into a chocolate-brown color. If it accumulates within the ovaries, it forms chocolate cysts, which can exert pressure and damage ovarian tissue, leading to adhesions between the ovaries, fallopian tubes, and surrounding tissues, thereby affecting pregnancy rates.